Oprah Winfrey, who has publicly struggled with her weight for decades, is going on a diet again. But this time she stands to gain a lot of money from her efforts.

Weight Watchers said Monday that it signed a five-year deal with the former talk show host. Winfrey, a co-owner of OWN: The Oprah Winfrey Network, is paying about $43.2 million for a 10 percent stake in the weight loss company.

The deal is already paying off: Weight Watchers shares more than doubled after the partnership was announced, earning Winfrey about $45 million on paper.

Winfrey will use the Weight Watchers mobile app and work with a personal coach, the company said. She has also agreed to let Weight Watchers use her name, image and likeness for its products and services. Additionally, she will make appearances on the company’s behalf.